Adjustable propeller cuff



Jan. 1, 1952 F, v, H, UDB 2,580,789

ADJUSTABLE PROPELLER CUFF Filed NOV. 5, 1945 2 SHEETS-SHEET l EQl.

Jan. 1, 1952 F, y, H JUDD 2,580,789

ADJUSTABLE PROPELLER CUFF Filed Nov. 5, 1945 2 SHEETS-SHEET 2 Patented `an. 139512 ADJUSTABLE PROPELLER cUFF Frederick V. H.- Judd, Canton, Conn., assigner to United Aircraft Corporation, -East Hartford, Conn., a corporation of Delaware.

Application November 5,1945, serial No. 626,647

This invention relates to aircraft propellers and has for its object to increase the eiectiveness of suchpropellers in coolingthe'aircraft engine.

Another object of the invention is to increase the'cooling effect of the cuff or shank fairing -of a'variable pitch aircraft propeller.

Still anotherv object is to provide a novel and improved combination of variable pitch propeller blades and cuffs in which the blades .andV cuffs are relatively adjustable to insure maximum operating eliciency.

Various other objects and advantages will ybe apparent as the nature of the invention is more fully disclosed.

As is well known, the shank of an aircraft propeller blade is normally substantially cylindrical and gradually fairs into a blade shape. [This normally cylindrical portion is now often encased in a member called a cuff or shank fairing which is of; substantially blade shape and is intended to produce an air stream useful in cooling the engine.

I Vhave now discovered that the cooling effectiveness of a blade cuff of the foregoing type may be materially increased by mounting the culi independently of the blade and making the two relatively adjustable to control the slip-stream velocity in accordance with various operating conditions.

In one embodiment of the invention, hereinafter described, the cuffs or shank fairings are detached from the blades of a variable pitch aircraft propeller, and means are provided for adjusting the pitch of the culs independently of the propeller blades. In another embodiment the cuffs are secured directly to the propeller hub or to the spinner on the nose section, independently of the variable pitch blades, with sufflcient adjustment provided to enable the optimum setting of the culis to be determined experimentally.

4 claims. (o1. 17o- 135.743) n.

ing purposes.

At the critical engine cooling. conditions of climb, take-oil and ground running, the angle of the variable-pitch propeller blades is lowl and for most eiective cooling the cuffs should be at a high angle to increase the pressure of the cooling stream of air. vides a simple and eflicient'means for accomplishing this result, and, in the case, of the variable pitch cuffs controlled by the pilot as hereinafter described, enables the settings of the cuffs and blades to be varied independently and at will, according to operating requirements.

Although the novel features which are characteristic of this invention are set forth more in detail in the claims appended hereto, the nature and scope of the invention may be better understood by referring to the following description, taken in connection with the accompanying drawing forming a part thereof, in which certain specific embodiments have been set forth for purposes of illustration.

"In the drawing:y

Figure -1 is adiagrammatic sectional view.

through the nose section of an airplane having independently adjustable propeller blades and cuffs in accordance with the present invention;

Fig. 2 -is a fragmentary' transverse section taken on line 2-2lof Fig. -1; and

Fig..3 is a similar View illustrating a modificar.

tion of. the invention. In the following description certain specific termsA are used for convenience in referring to the various details of ,the invention. These` terms, however, are to beinterpreted as broadly as ,the state of the art will permit.

In the drawing, Fig. 1 shows the nose sectionk I of anairplane power plant driving the rotatable propeller hub I2 and the surroundingvr spinner I3. The power plant is enclosed in a conventional cowling as Vshown diagrammatically at II in Fig. l, thus providing an annular space I I a through which air wsfor cooling the power .plantel A plurality of lpropeller blades I 4 have their Shanks I'journaled in suitable bearings (not shown) inthe vhiibIZ, permitting said blades to be rotated axially in the hub I2'for pitch adjust- Any suitablev means may be employed` for thus varying the pitchv of the blades I4.

propeller assembly. Y'

Surrounding the substantially cylindrical shank I5 of each propeller blade I4, and detached from said shank, is afcuff or fairing member I6 of any suitable material having a llanged cylindrical liner I'l -which is journaled in a bearing I8 carried by the spinner I3, permitting said cuff I6 to be rotated axiallyupon said bearing. If desired, however, the cuff IB may be rotatably mounted on the hub I 2 instead of on the spinner I3. Y

-The cuffs I6 may be rotated axially ontheir bearingslin any desired manner. The adjusting v means illustrated schematically in Fig. 1

.3 comprises a control rod I9 operated by the pilot of the airplane vand movable tothe right or left The present invention proas viewed -in Fig. 1. The rod I9 actuates a flanged collar 2li which-is loosely mounted on the rotatable propeller hub I2, enabling the non-rotating collar 20 to be moved axially of the hub I2. The collar 20 contains a peripheral slot 2I into which extends the arms 22 which are secured to rods 23, Figs. 1 and 2, slidably mounted in bearings 24`on the'spinner I3. there being one such arm 22 and rod 23 for each propeller blade I4. Each rod 23has a pin 25 loosely engaged in a hole formed in a lug 26 on the cuff liners I'I of the respective propeller blades. Movement of the control rod I9 to the right or left, as viewed non-rotatablecollar 20, Athe arms 22, rods l23 and The rotatable members including the hub I2,`v the bladeslll, the spinner I3 vand parts rotated therewith by the power plant may be termed then pin's 25, thereby rotating the cuffs I6 upon their bearings I8. The cuffs I6 may thus be rota-ted or twisted axially to vary their pitch independently of the propeller blades I4.

In the embodiment illustrated in Fig. 1, the cuff I9 surrounds the shank I5 of blade' I`4 for only a limited distance, encompassing that'portion of the shank which is substantially cylindrical in cross-section. The outer portion of the Y shank which gradually fairs into a propeller blade shape is encased in a ilxed fairing section 21 of rubber or other suitable material.

Fig. 3 illustrates a modification of the invention, in which the cuff I6 is secured directlytoa place Z9 which is rigidly secured to the spinner I3 or to the hub I2. In the form illustrated, the cull' is secured to plate 2a by means or bolts 3u which extend through the inner Ilange of cuff liner I`l and through arcuate noies in plate 29. By suitably adjusting the cuff Io before tightening the bolts 3u the optimum setting of tne cuIf may be determined experimentally. After the desired adjustment has been en'ected tlie cud Iu' remains nxed in Iiight, while the blades i4 may be rotated in night to vary their pitcii as in the embodiment previously described. This adjustment in the iorlll shown in rig. 3 would require a disassembly or tile propeller assembly t glVe aCCeSS EO En@ DOlDS 311. 1D 1S col'lemplaled.'

however, that other devices having equivalent functions could be arranged to give easier access for providing this adjustment.

Although certain specific embodiments have been shown and described herein for purposes of illustration, it will be evident to those skilled in the art that the invention is capable of various modifications and adaptations within the scope of the appended claims.

What is claimed is:

1. The combination with an aircraft power plant having a cowling spaced therefrom to provide an annular space ior air now around thev power plant, a propeller assembly including a plurality of adjustable pitch blades, and a spinner forming a part of said assembly, 4of a pliirality of cuis carried by said spinner, each said curi surrounding and spaced from al shank porv-V tion of each of said blades respectively, each of said cuffs being formed as afan blade, sowas to force air through said annular space upon the rotation of said propeller assembly, wrneans independent of the pitch of said blades for Iad justably securing said cuffs respectively to vsaid spinner including a plurality of bolts and Aa flange member rigidly carried by eachaid enfin-,and having arcuate slots through which s aidbolts pass and are threaded into a part of said spinner, said slots being arrangedA substantially concentric with the shank portions of lthe associated blade shank, so that said cuffs maybe adjusted by loosening said bolts, manually turningy said cuffs to any predeterminedpitch positionthere: of within the limits of adjustment, andhthen tightening saidnbolts to secure the adjustment when made, the cuff adjusting means being 4so constructed and arranged that vthe pitch adjustment of said cuffs will be effective to control air flow through said annular space for va'ny given speed of rotation of said propeller assembly. I

2. The combination with an aircraftvpower plant having a cowling spaced therefrom topifo# vide an annular space for air flow around the power plant, and a propellerassmblyai'ota-table about a predeterminedy axis andincluding a plu;-l

' independent of the pitch of said blades for supporting said cuffs fromf said assembly so that saidcuffs may be rotatably adjusted about the longitudinal axes of the respectively associated blades including a bearing means intermediate said assemblyl and each of said cuffs 'arranged substantially concentric with the shank portions of said blades respectively; and means independent of the pitch of said blades and any adjustments thereof for simultaneously rotatably ad justing the pitch of all said cuffs about the axes of their respectively associated blades, including a means articulated to each of said cuffs and mounted for rotation with said propeller assembly and movable axially thereof, means nonrotatable with said assembly and mechanically connected so as simultaneously to move all the last named means. and means for moving said non-rotatable means axially in respect to said assembly.

3. ille combination with an aircraft power plant having a cowling spaced therefrom to provide an annular space for air rlow around the power plant, a propeller assembly including a plurality of adjustable pitch blades, and a spinner forming a part of said assembly, of a plu'- rality of cuffs carried by said spinner, each said culf surrounding and spaced fromI a shank portion of each of said blades respectively, each of said cus being formed as a fan blade for forcing air through said annular space upon the rotation of said propeller assembly, and means for mounting each of said cuffs on said spinner 'and for adjustably varying the pitch of said cuffs, the last` named `nieans'being independent 4of said blades and of the pitch adjustmer'it thereof.

4. Apparatus in 'accordance with claim 3, wherein said last named means includes nie'a'ris operable during :the rotation of said propeller assembly in use for adjustably varying the pitch of s'aidcufs. u

FREDERICK V. H. JUDI).

REFERENCES CITED The` following references are of record in the file of this patent: 

